Prior art systems that guide a manned or unmanned vehicle on an approach to a particular position are varied in the techniques, apparatus and complexity. For example, in terms of underwater guidance, autonomous docking of unmanned underwater vehicles (UUVs) requires a higher degree of accuracy than is available using standard UUV navigation equipment such as an Inertial Navigation Unit (INU) or the Global Positioning System (GPS). Although UUVs have been autonomously docked by augmenting INU and GPS data with acoustical homing, such systems still lack precision and have required the use of large docking cones to perform the final close-range alignment and docking of the vehicle. The large size and weight of the docking cones make them impractical to carry onboard a UUV.
A United States Office of Naval Research paper entitled “Underwater Docking of Autonomous Undersea Vehicles Using Optical Terminal Guidance,” by Cowen et al, IEEE Oceans '97, Halifax, NS, October 1997, describes a system that uses a single light source to guide a UUV to a docking station. Although it provides a good degree of accuracy, this system only aligns the UUV with the light's position and does not provide any guidance corrections to achieve a preferred line of approach.